On Wed, Dec 12, 2018 at 9:28 PM Tomas Vondra <tomas.von...@2ndquadrant.com>
wrote:
>
> Can you also update the docs to mention that the functions called from
> the WHERE clause does not see effects of the COPY itself?
>
>
*Of course, i also add same comment to insertion method selection*
*regards *
*Surafel*
diff --git a/doc/src/sgml/ref/copy.sgml b/doc/src/sgml/ref/copy.sgml
index 411941ed31..4e6eb1fcdb 100644
--- a/doc/src/sgml/ref/copy.sgml
+++ b/doc/src/sgml/ref/copy.sgml
@@ -25,6 +25,7 @@ PostgreSQL documentation
COPY <replaceable class="parameter">table_name</replaceable> [ ( <replaceable class="parameter">column_name</replaceable> [, ...] ) ]
FROM { '<replaceable class="parameter">filename</replaceable>' | PROGRAM '<replaceable class="parameter">command</replaceable>' | STDIN }
[ [ WITH ] ( <replaceable class="parameter">option</replaceable> [, ...] ) ]
+ [ WHERE <replaceable class="parameter">condition</replaceable> ]
COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable class="parameter">column_name</replaceable> [, ...] ) ] | ( <replaceable class="parameter">query</replaceable> ) }
TO { '<replaceable class="parameter">filename</replaceable>' | PROGRAM '<replaceable class="parameter">command</replaceable>' | STDOUT }
@@ -353,6 +354,31 @@ COPY { <replaceable class="parameter">table_name</replaceable> [ ( <replaceable
</listitem>
</varlistentry>
+ <varlistentry>
+ <term><literal>WHERE</literal></term>
+ <listitem>
+ <para>
+ The optional <literal>WHERE</literal> clause has the general form
+<synopsis>
+WHERE <replaceable class="parameter">condition</replaceable>
+</synopsis>
+ where <replaceable class="parameter">condition</replaceable> is
+ any expression that evaluates to a result of type
+ <type>boolean</type>. Any row that does not satisfy this
+ condition will not be inserted to the table. A row satisfies the
+ condition if it returns true when the actual row values are
+ substituted for any variable references.
+ </para>
+
+ <para>
+ Currently, <literal>WHERE</literal> expressions cannot contain
+ subqueries and will not see changes made by <command>COPY</command>
+ command in a case of <literal>VOLATILE</literal> function.
+ </para>
+
+ </listitem>
+ </varlistentry>
+
</variablelist>
</refsect1>
diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
index 4aa8890fe8..b0471eedab 100644
--- a/src/backend/commands/copy.c
+++ b/src/backend/commands/copy.c
@@ -40,7 +40,11 @@
#include "miscadmin.h"
#include "optimizer/clauses.h"
#include "optimizer/planner.h"
+#include "optimizer/prep.h"
#include "nodes/makefuncs.h"
+#include "parser/parse_coerce.h"
+#include "parser/parse_collate.h"
+#include "parser/parse_expr.h"
#include "parser/parse_relation.h"
#include "port/pg_bswap.h"
#include "rewrite/rewriteHandler.h"
@@ -150,6 +154,7 @@ typedef struct CopyStateData
bool convert_selectively; /* do selective binary conversion? */
List *convert_select; /* list of column names (can be NIL) */
bool *convert_select_flags; /* per-column CSV/TEXT CS flags */
+ Node *whereClause; /* WHERE condition (or NULL) */
/* these are just for error messages, see CopyFromErrorCallback */
const char *cur_relname; /* table name for error messages */
@@ -180,6 +185,7 @@ typedef struct CopyStateData
ExprState **defexprs; /* array of default att expressions */
bool volatile_defexprs; /* is any of defexprs volatile? */
List *range_table;
+ ExprState *qualexpr;
TransitionCaptureState *transition_capture;
@@ -801,6 +807,7 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
Relation rel;
Oid relid;
RawStmt *query = NULL;
+ Node *whereClause = NULL;
/*
* Disallow COPY to/from file or program except to users with the
@@ -854,6 +861,25 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
NULL, false, false);
rte->requiredPerms = (is_from ? ACL_INSERT : ACL_SELECT);
+ if (stmt->whereClause)
+ {
+ /* add rte to column namespace */
+ addRTEtoQuery(pstate, rte, false, true, true);
+
+ /* Transform the raw expression tree */
+ whereClause = transformExpr(pstate, stmt->whereClause, EXPR_KIND_COPY_WHERE);
+
+ /* Make sure it yields a boolean result. */
+ whereClause = coerce_to_boolean(pstate, whereClause, "WHERE");
+ /* we have to fix its collations too */
+ assign_expr_collations(pstate, whereClause);
+
+ whereClause = eval_const_expressions(NULL, whereClause);
+
+ whereClause = (Node *) canonicalize_qual((Expr *) whereClause, false);
+ whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
+ }
+
tupDesc = RelationGetDescr(rel);
attnums = CopyGetAttnums(tupDesc, rel, stmt->attlist);
foreach(cur, attnums)
@@ -1002,6 +1028,7 @@ DoCopy(ParseState *pstate, const CopyStmt *stmt,
cstate = BeginCopyFrom(pstate, rel, stmt->filename, stmt->is_program,
NULL, stmt->attlist, stmt->options);
+ cstate->whereClause = whereClause;
*processed = CopyFrom(cstate); /* copy from file to database */
EndCopyFrom(cstate);
}
@@ -2531,6 +2558,10 @@ CopyFrom(CopyState cstate)
if (cstate->rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
proute = ExecSetupPartitionTupleRouting(NULL, cstate->rel);
+ if (cstate->whereClause)
+ cstate->qualexpr = ExecInitQual(castNode(List, cstate->whereClause),
+ &mtstate->ps);
+
/*
* It's more efficient to prepare a bunch of tuples for insertion, and
* insert them in one heap_multi_insert() call, than call heap_insert()
@@ -2576,6 +2607,16 @@ CopyFrom(CopyState cstate)
*/
insertMethod = CIM_SINGLE;
}
+ else if (cstate->whereClause != NULL ||
+ contain_volatile_functions(cstate->whereClause))
+ {
+ /*
+ * Can't support multi-inserts if there are any volatile funcation
+ * expressions in WHERE clause. Similarly to the trigger case above,
+ * such expressions may query the table we're inserting into.
+ */
+ insertMethod = CIM_SINGLE;
+ }
else
{
/*
@@ -2679,6 +2720,13 @@ CopyFrom(CopyState cstate)
slot = myslot;
ExecStoreHeapTuple(tuple, slot, false);
+ if (cstate->whereClause)
+ {
+ econtext->ecxt_scantuple = myslot;
+ if (!ExecQual(cstate->qualexpr, econtext))
+ continue;
+ }
+
/* Determine the partition to heap_insert the tuple into */
if (proute)
{
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index db49968409..a3753d899e 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -3309,6 +3309,7 @@ _copyCopyStmt(const CopyStmt *from)
COPY_SCALAR_FIELD(is_program);
COPY_STRING_FIELD(filename);
COPY_NODE_FIELD(options);
+ COPY_NODE_FIELD(whereClause);
return newnode;
}
diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 3a084b4d1f..a44013f0e6 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -1221,6 +1221,7 @@ _equalCopyStmt(const CopyStmt *a, const CopyStmt *b)
COMPARE_SCALAR_FIELD(is_program);
COMPARE_STRING_FIELD(filename);
COMPARE_NODE_FIELD(options);
+ COMPARE_NODE_FIELD(whereClause);
return true;
}
diff --git a/src/backend/parser/gram.y b/src/backend/parser/gram.y
index 2c2208ffb7..437b8c38b9 100644
--- a/src/backend/parser/gram.y
+++ b/src/backend/parser/gram.y
@@ -509,7 +509,6 @@ static Node *makeRecursiveViewSelect(char *relname, List *aliases, Node *query);
%type <defelt> copy_generic_opt_elem
%type <list> copy_generic_opt_list copy_generic_opt_arg_list
%type <list> copy_options
-
%type <typnam> Typename SimpleTypename ConstTypename
GenericType Numeric opt_float
Character ConstCharacter
@@ -2962,7 +2961,8 @@ ClosePortalStmt:
*****************************************************************************/
CopyStmt: COPY opt_binary qualified_name opt_column_list
- copy_from opt_program copy_file_name copy_delimiter opt_with copy_options
+ copy_from opt_program copy_file_name copy_delimiter opt_with
+ copy_options where_clause
{
CopyStmt *n = makeNode(CopyStmt);
n->relation = $3;
@@ -2971,6 +2971,7 @@ CopyStmt: COPY opt_binary qualified_name opt_column_list
n->is_from = $5;
n->is_program = $6;
n->filename = $7;
+ n->whereClause = $11;
if (n->is_program && n->filename == NULL)
ereport(ERROR,
@@ -2978,6 +2979,12 @@ CopyStmt: COPY opt_binary qualified_name opt_column_list
errmsg("STDIN/STDOUT not allowed with PROGRAM"),
parser_errposition(@8)));
+ if (!n->is_from && n->whereClause != NULL)
+ ereport(ERROR,
+ (errcode(ERRCODE_SYNTAX_ERROR),
+ errmsg("WHERE clause not allowed with COPY TO"),
+ parser_errposition(@11)));
+
n->options = NIL;
/* Concatenate user-supplied flags */
if ($2)
diff --git a/src/backend/parser/parse_agg.c b/src/backend/parser/parse_agg.c
index 61727e1d71..506cb53214 100644
--- a/src/backend/parser/parse_agg.c
+++ b/src/backend/parser/parse_agg.c
@@ -523,6 +523,14 @@ check_agglevels_and_constraints(ParseState *pstate, Node *expr)
break;
+ case EXPR_KIND_COPY_WHERE:
+ if (isAgg)
+ err = _("aggregate functions are not allowed in COPY FROM WHERE conditions");
+ else
+ err = _("grouping operations are not allowed in COPY FROM WHERE conditions");
+
+ break;
+
/*
* There is intentionally no default: case here, so that the
* compiler will warn if we add a new ParseExprKind without
@@ -902,6 +910,9 @@ transformWindowFuncCall(ParseState *pstate, WindowFunc *wfunc,
case EXPR_KIND_CALL_ARGUMENT:
err = _("window functions are not allowed in CALL arguments");
break;
+ case EXPR_KIND_COPY_WHERE:
+ err = _("window functions are not allowed in COPY FROM WHERE conditions");
+ break;
/*
* There is intentionally no default: case here, so that the
diff --git a/src/backend/parser/parse_expr.c b/src/backend/parser/parse_expr.c
index 385e54a9b6..6b96a23173 100644
--- a/src/backend/parser/parse_expr.c
+++ b/src/backend/parser/parse_expr.c
@@ -1849,6 +1849,9 @@ transformSubLink(ParseState *pstate, SubLink *sublink)
case EXPR_KIND_CALL_ARGUMENT:
err = _("cannot use subquery in CALL argument");
break;
+ case EXPR_KIND_COPY_WHERE:
+ err = _("cannot use subquery in COPY FROM WHERE condition");
+ break;
/*
* There is intentionally no default: case here, so that the
@@ -3475,6 +3478,8 @@ ParseExprKindName(ParseExprKind exprKind)
return "PARTITION BY";
case EXPR_KIND_CALL_ARGUMENT:
return "CALL";
+ case EXPR_KIND_COPY_WHERE:
+ return "WHERE";
/*
* There is intentionally no default: case here, so that the
diff --git a/src/backend/parser/parse_func.c b/src/backend/parser/parse_func.c
index 44257154b8..9dafa7084a 100644
--- a/src/backend/parser/parse_func.c
+++ b/src/backend/parser/parse_func.c
@@ -2370,6 +2370,9 @@ check_srf_call_placement(ParseState *pstate, Node *last_srf, int location)
case EXPR_KIND_CALL_ARGUMENT:
err = _("set-returning functions are not allowed in CALL arguments");
break;
+ case EXPR_KIND_COPY_WHERE:
+ err = _("set-returning functions are not allowed in COPY FROM WHERE conditions");
+ break;
/*
* There is intentionally no default: case here, so that the
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index e5bdc1cec5..b80a1561be 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -1969,6 +1969,7 @@ typedef struct CopyStmt
bool is_program; /* is 'filename' a program to popen? */
char *filename; /* filename, or NULL for STDIN/STDOUT */
List *options; /* List of DefElem nodes */
+ Node *whereClause; /* WHERE condition (or NULL) */
} CopyStmt;
/* ----------------------
diff --git a/src/include/parser/parse_node.h b/src/include/parser/parse_node.h
index 0230543810..6f569a5265 100644
--- a/src/include/parser/parse_node.h
+++ b/src/include/parser/parse_node.h
@@ -69,7 +69,8 @@ typedef enum ParseExprKind
EXPR_KIND_TRIGGER_WHEN, /* WHEN condition in CREATE TRIGGER */
EXPR_KIND_POLICY, /* USING or WITH CHECK expr in policy */
EXPR_KIND_PARTITION_EXPRESSION, /* PARTITION BY expression */
- EXPR_KIND_CALL_ARGUMENT /* procedure argument in CALL */
+ EXPR_KIND_CALL_ARGUMENT, /* procedure argument in CALL */
+ EXPR_KIND_COPY_WHERE /* WHERE condition in COPY FROM */
} ParseExprKind;
diff --git a/src/interfaces/ecpg/preproc/ecpg.addons b/src/interfaces/ecpg/preproc/ecpg.addons
index 0167ee4620..821d93ef07 100644
--- a/src/interfaces/ecpg/preproc/ecpg.addons
+++ b/src/interfaces/ecpg/preproc/ecpg.addons
@@ -192,7 +192,7 @@ ECPG: where_or_current_clauseWHERECURRENT_POFcursor_name block
char *cursor_marker = $4[0] == ':' ? mm_strdup("$0") : $4;
$$ = cat_str(2,mm_strdup("where current of"), cursor_marker);
}
-ECPG: CopyStmtCOPYopt_binaryqualified_nameopt_column_listcopy_fromopt_programcopy_file_namecopy_delimiteropt_withcopy_options addon
+ECPG: CopyStmtCOPYopt_binaryqualified_nameopt_column_listcopy_fromopt_programcopy_file_namecopy_delimiteropt_withcopy_optionswhere_clause addon
if (strcmp($6, "from") == 0 &&
(strcmp($7, "stdin") == 0 || strcmp($7, "stdout") == 0))
mmerror(PARSE_ERROR, ET_WARNING, "COPY FROM STDIN is not implemented");
diff --git a/src/test/regress/expected/copy2.out b/src/test/regress/expected/copy2.out
index 19bb538411..2ba88eed89 100644
--- a/src/test/regress/expected/copy2.out
+++ b/src/test/regress/expected/copy2.out
@@ -49,6 +49,28 @@ CONTEXT: COPY x, line 1: "2002 232 40 50 60 70 80"
COPY x (b, c, d, e) from stdin delimiter ',' null 'x';
COPY x from stdin WITH DELIMITER AS ';' NULL AS '';
COPY x from stdin WITH DELIMITER AS ':' NULL AS E'\\X' ENCODING 'sql_ascii';
+COPY x from stdin WHERE a = 50004;
+COPY x from stdin WHERE a > 60003;
+COPY x from stdin WHERE f > 60003;
+ERROR: column "f" does not exist
+LINE 1: COPY x from stdin WHERE f > 60003;
+ ^
+COPY x from stdin WHERE a = max(x.b);
+ERROR: aggregate functions are not allowed in COPY FROM WHERE conditions
+LINE 1: COPY x from stdin WHERE a = max(x.b);
+ ^
+COPY x from stdin WHERE a IN (SELECT 1 FROM x);
+ERROR: cannot use subquery in COPY FROM WHERE condition
+LINE 1: COPY x from stdin WHERE a IN (SELECT 1 FROM x);
+ ^
+COPY x from stdin WHERE a IN (generate_series(1,5));
+ERROR: set-returning functions are not allowed in COPY FROM WHERE conditions
+LINE 1: COPY x from stdin WHERE a IN (generate_series(1,5));
+ ^
+COPY x from stdin WHERE a = row_number() over(b);
+ERROR: window functions are not allowed in COPY FROM WHERE conditions
+LINE 1: COPY x from stdin WHERE a = row_number() over(b);
+ ^
-- check results of copy in
SELECT * FROM x;
a | b | c | d | e
@@ -73,12 +95,15 @@ SELECT * FROM x;
4006 | 6 | BackslashN | \N | before trigger fired
4007 | 7 | XX | XX | before trigger fired
4008 | 8 | Delimiter | : | before trigger fired
+ 50004 | 25 | 35 | 45 | before trigger fired
+ 60004 | 25 | 35 | 45 | before trigger fired
+ 60005 | 26 | 36 | 46 | before trigger fired
1 | 1 | stuff | test_1 | after trigger fired
2 | 2 | stuff | test_2 | after trigger fired
3 | 3 | stuff | test_3 | after trigger fired
4 | 4 | stuff | test_4 | after trigger fired
5 | 5 | stuff | test_5 | after trigger fired
-(25 rows)
+(28 rows)
-- check copy out
COPY x TO stdout;
@@ -102,6 +127,9 @@ COPY x TO stdout;
4006 6 BackslashN \\N before trigger fired
4007 7 XX XX before trigger fired
4008 8 Delimiter : before trigger fired
+50004 25 35 45 before trigger fired
+60004 25 35 45 before trigger fired
+60005 26 36 46 before trigger fired
1 1 stuff test_1 after trigger fired
2 2 stuff test_2 after trigger fired
3 3 stuff test_3 after trigger fired
@@ -128,6 +156,9 @@ N before trigger fired
BackslashN before trigger fired
XX before trigger fired
Delimiter before trigger fired
+35 before trigger fired
+35 before trigger fired
+36 before trigger fired
stuff after trigger fired
stuff after trigger fired
stuff after trigger fired
@@ -154,6 +185,9 @@ I'm null before trigger fired
6 before trigger fired
7 before trigger fired
8 before trigger fired
+25 before trigger fired
+25 before trigger fired
+26 before trigger fired
1 after trigger fired
2 after trigger fired
3 after trigger fired
diff --git a/src/test/regress/sql/copy2.sql b/src/test/regress/sql/copy2.sql
index e36df8858e..0bf23c6976 100644
--- a/src/test/regress/sql/copy2.sql
+++ b/src/test/regress/sql/copy2.sql
@@ -95,6 +95,31 @@ COPY x from stdin WITH DELIMITER AS ':' NULL AS E'\\X' ENCODING 'sql_ascii';
4008:8:Delimiter:\::\:
\.
+COPY x from stdin WHERE a = 50004;
+50003 24 34 44 54
+50004 25 35 45 55
+50005 26 36 46 56
+\.
+
+COPY x from stdin WHERE a > 60003;
+60001 22 32 42 52
+60002 23 33 43 53
+60003 24 34 44 54
+60004 25 35 45 55
+60005 26 36 46 56
+\.
+
+COPY x from stdin WHERE f > 60003;
+
+COPY x from stdin WHERE a = max(x.b);
+
+COPY x from stdin WHERE a IN (SELECT 1 FROM x);
+
+COPY x from stdin WHERE a IN (generate_series(1,5));
+
+COPY x from stdin WHERE a = row_number() over(b);
+
+
-- check results of copy in
SELECT * FROM x;
